I have two modern machines: one embroidery and one "cheapie" I bought to take to class along with a serger. THEN, I started looking for a treadle because I think they are beautiful and love the history behind them. So, now, I have one 66-1 treadle, one 115 treadle head looking for a base, one 201 hand crank (my favorite), two featherweights and a 328. My DH and I love the history and beauty of them all. We were recently gifted DH's great grandmother's 127 treadle, but it is in sad shape. It has been in a barn for 20+ years but after seeing some of the miraculous restorations here on the board, we think the machine and irons can be saved. The cabinet may not be able to be saved. I use all of them, especially the featherweights and the 201. I rarely use my modern machines unless a class project requires a special stitch.
So, I guess we are just collectors and the items we happen to collect have purpose.
Some people collect shoes - how many can you wear at once? To each his own. I am enjoying my collecting just like others enjoy their shoes, stamps, or whatever! Give a vintage machine a try!